Velocity of the projectile, v=140m∕s The angle of projection, θ=60∘. The horizontal component of the velocity is always constant throughout the motion. Let the velocity is u when the angle is 30∘ with horizontal. ∴vcos60∘=ucos30∘ ⇒
v
2
=
√3u
2
⇒u=
v
√3
=
140
√3
m∕s For vertical motion, uy−vy=gt ⇒vsin60∘−usin30∘=gt ⇒
